Adventures & experiences in contemporary technology
Having seen Linux Format cover tools like Vagrant and Puppet that manage virtual machines, I have been attracted by the prospect of a virtual web server running on my own PC. Certainly, having the LAMP software stack in a VM means that the corresponding tools don’t need to be added to a host system should its operating system need a fresh installation.
As intriguing as tools like Vagrant may be, I decided that I needed to learn a bit more about getting server instances set up in VirtualBox anyway. Thus, I went and downloaded the latest version of Ubuntu Server and gave that a go. One lesson that I learned was that Bridged Networking needs to be added to the VM before installation of the operating system unless you fancy overcoming the challenge of getting Ubuntu Server to recognise an altered or additional network interface. In my case, I added an extra adapter for the Bridged Networking and left the original in place as NAT. The reason for having Bridged Networking set up is that it allows access to the virtual web server from the host once you know the IP address and that information can be obtained by executing the ifconfig command on the virtual machine.
With the networking sorted, the next step was to install the 64-bit edition of Ubuntu Server. Unlike its desktop counterpart, this is all driven by text menus but remains fairly intuitive and there is hardly anything there that you wouldn’t see with another Linux distribution. A useful addition is the addition of a menu to select the type of server services that you’d like to see installed. From this, I chose the web server and SSH options and I seem to remember that there was a database server option too. If there was an FTP server option, I would have chosen that too but it was no ordeal to add ProFTPd later on anyway.
All of this set was done through the VirtualBox GUI just to keep life more straightforward. Even so, I only selected 12 MB of video memory and was tempted to cut the overall memory back from 512 MB but leaving things be for now. However, what I have begun to do is start and stop the virtual machine from the command line since servers are headless operations anyway. With SSH enabled, there is little need to have the VirtualBox GUI going. The command for starting the server is below:
VBoxManage startvm "Ubuntu Server" --type=headless
There is a VBoxHeadless command for the same end too but VBoxManage does what I need. The startvm option is what tells VBoxManage to start the server and the virtual machine’s name is enclosed in quotes. The --type=headless ensures that no window pops up. To stop the virtual web server cleanly, a command like the following is needed:
VBoxManage controlvm "Ubuntu Server" acpipowerbutton
Again, the VBoxManage command gets used and the acpipowerbutton option ensures that a clean shutdown is performed. Not doing so results in the server not fully starting up according to my experiences thus far. Getting the virtual web server to start and stop with the host machine itself starting and stopping but this looks more complex so I plan to leave things a while before trying that experiment.
Seeing Arch Linux running so solidly in a VirtualBox virtual box has me contemplating whether I should have it installed on a real PC. Saying that, recent announcements regarding the implementation of GNOME 3 in Linux Mint have caught my interest even if the idea of using a rolling distribution as my main home operating system still has a lot of appeal for me. Having an upheaval come my way every six months when a new version of Linux Mint is released is the main cause of that.
While remaining undecided, I continue to evaluate the idea of Arch Linux acting as my main OS for day-to-day home computing. Towards that end, I have set up a working web server instance on there using the usual combination of Apache, Perl, PHP and MySQL. Of these, it was MySQL that went the least smoothly of all because the daemon wouldn’t start for me.
It was then that I started to turn to Google for inspiration and a range of actions resulted that combined to give the result that I wanted. One problem was a lack of disk space caused by months of software upgrades. Since tools like it in other Linux distros allow you to clear some disk space of obsolete installation files, I decided to see if it was possible to do the same with pacman, the Arch Linux command line package manager. The following command, executed as root, cleared about 2 GB of cruft for me:
pacman -Sc
The S in the switch tells pacman to perform package database synchronization while the c instructs it to clear its cache of obsolete packages. In fact, using the following command as root every time an update is performed both updates software and removes redundant or outmoded packages:
pacman -Syuc
So I don’t forget the needful housekeeping, this will be what I use in future with the y being the switch for a refresh and the u triggering a system upgrade. It’s nice to have everything happen together without too much effort.
To do the required debugging that led me to the above along with other things, I issued the following command:
mysqld_safe --datadir=/var/lib/mysql/ &
This starts up the MySQL daemon in safe mode if all is working properly and it wasn’t in my case. Nevertheless, it creates a useful log file called myhost.err in /var/lib/mysql/. This gave me the messages that allowed the debugging of what was happening. It led me to installing net-tools and inettools using pacman; it was the latter of these that put hostname on my system and got the MySQL server startup a little further along. Other actions included unlocking the ibdata1 data file and removing the ib_logfile0 and ib_logfile1 files so as to gain something of a clean sheet. The kill command was used to shut down any lingering mysqld sessions too. To ensure that the ibdata1 file was unlocked, I executed the following commands:
mv ibdata1 ibdata1.bad
cp -a ibdata1.bad ibdata1
These renamed the original and then crated a new duplicate of it with the -a switch on the cp command forcing copying with greater integrity than normal. Along with the various file operations, I also created a link to my.cnf, the MySQL configuration file on Linux systems, in /etc using the following command executed by root:
ln -s /etc/mysql/ my.cnf /etc/my.cnf
While I am unsure if this made a real difference, uncommenting the lines in the same file that pertained to InnoDB tables. What directed me to these were complaints from mysqld_safe in the myhost.err log file. All I did was to uncomment the lines beginning with “innodb” and these were 116-118, 121-122 and 124-127 in my configuration file but it may be different in yours.
After all the above, the MySQL daemon ran happily and, more importantly, started when I rebooted the virtual machine. Thinking about it now, I believe that was a lack of disk space, the locking of a data file and the lack of InnoDB support that was stopping the MySQL service from running.Running commands like mysqld start weren’t yielding useful messages so a lot of digging was needed to get the result that I needed. In fact, that’s one of the reasons why I am sharing my experiences here.
In the end, creating databases and loading them with data was all that was needed for me to start see functioning websites on my (virtual) Arch Linux system. It turned out to be another step on the way to making it workable as a potential replacement for the Linux distributions that I use most often (Linux Mint, Fedora and Ubuntu).
A move from Outlook 2000 to Outlook 2007 at work before Christmas resulted in deactivated Outlook rules and messages like the following when I tried reactivating them:
One or more rules could not be uploaded to Exchange server and have been deactivated. This could be because some of the parameters are not supported or there is insufficient space to store all your rules.
The cause is a 32 KB size limitation for all rules associated with your Exchange server account prior to Exchange 2007. With the latter, the default size increases to 64 KB and can be increased further to 256 KB by manual intervention. This wouldn’t be a big issue if you had the option to store rules locally on your own PC but that was removed after Outlook 2000, therefore explaining why I first encountered it when I did. Microsoft has a useful article on their support website containing suggested remedies and they aren’t all as extreme as deleting some rules either. Consolidation and shortening of rule names are other suggestions and you should never discount how much space the “run on this machine only” parameter takes up either. Still, it’s an odd design decision that caused this but I suppose that it wouldn’t the first made by Microsoft and it may not be the last either.
Here’s a trick that might have its uses: using a local WordPress instance to update your online blog (yes, there are plenty of applications that promise to edit your online blog but these need file permissions to the likes of xmlrpc.php to be opened up). Along with the right database access credentials and the ability to log in remotely, adding the following two lines to wp-config.php does the trick:
define('WP_SITEURL', 'http://localhost/blog');
define('WP_HOME', 'http://localhost/blog');
These two constants override what is in the database and allow to update the online database from your own PC using WordPress running on a local web server (Apache or otherwise). One thing to remember here is that both online and offline directory structures are similar. For example, if your online WordPress files are in blog in the root of the online web server file system (typically htdocs for Linux), then they need to be contained in the same directory in the root of the offline server too. Otherwise, things could get confusing and perhaps messy. Another thing to consider is that you are modifying your online blog so the usual rules about care and attention apply, particularly with respect to using the same version of WordPress both locally and remotely. This is especially a concern if you, like me, run development versions of WordPress to see if there are any upheavals ahead of us like the overhaul that is coming in with WordPress 2.7.
An alternative use of this same trick is to keep a local copy of your online database in case of any problems while using a local WordPress instance to work with it. I used to have to edit the database backup directly (on my main Ubuntu system), first with GEdit but then using a sed command like the following:
sed -e s/www\.onlinewebsite\.com/localhost/g backup.sql > backup_l.sql
The -e switch uses regular expression substitution that follows it to edit the input with the output being directed to a new file. It’s slicker than the interactive GEdit route but has been made redundant by defining constants for a local WordPress installation as described above.
The last week on WordPress.com has featured decisions that some may question, to say the least. For instance, the death of Feed Stats was something that I saw as a retrograde step. Next, I saw a slight change to the appearance of my blog that led me to take full control of the situation; a previous discussion with WordPress.com staff about changing a theme to the way that I wanted it to be got me nowhere so I wasn’t about to try again… I might miss having advance notice of where WordPress goes next but I am not sure that I want to be a guinea pig either.
So, you now find this hosted by Streamline.net and, apart from a lengthy hiatus (at least, it felt like forever thanks to recurring thoughts of PageRank loss; yes, I know that sounds silly…) spent awaiting FTP access to be sorted out, the set up ran smoothly enough; I think that my request for transfer from a Windows server to a Linux one might have been the cause of the delay. Setting up a MySQL database was a breeze and it’s part of the package too. In fact, the Pro package that I am using is £31.99 ex VAT per annum, not bad at all, and, teething problems out of the way, it’ll be interesting to see how things will fare from now on.
Having a self-hosted WordPress installation is nothing new to me since I do it for my hillwalking blog and everything came together very quickly this time around. knowing what plug-ins add real value was a definite help: Bad Behaviour and Ultimate GA headed the list but a Spam Karma 2 is another option. Feedburner integration is another potential item on the configuration list. I have stuck with the Andreas09 theme but am unsure as to how far I will take customising it; it’s not a high priority right now. In fact, I may find another three-column layout that takes my eye now that I am not limited to the offerings available from WordPress.com.
The posts from the old blog have arrived over here and that seems to have worked fine first time around thanks the WordPress’ import/export functionality. I still have to get the images over but there’ll be time for that yet. Another thing on the to do list is to transfer over the links and set up any text and RSS widgets that have been a feature of the previous rendition of the blog. That means linking to wp-links-opml.php on the old blog using the import links functionality. There is no other link export function and you can only import into a single category; a link import/export plug-in that retains the link category information would be a bonus.
While I wonder if I have made a rod for my own back with my having two self-hosted WordPress blogs, it does feel good to have more control and it’ll be interesting where where this journey goes next.